Hello there, Having just rebuilt my Triumph 1500 engine I am now trying to get my twin 40's to run right... At idle the car runs fine, perhaps a little on the rich side, but nothing too major. Above 2,500rpm it also runs fine, plenty of pull and no missing. Between 1,700 - 2,500 rpm-ish on light throttle, it runs like an old dog, coughing and spitting from the carbs across all four pots, and occasionally a huge flame from the carbs and absolutely no power. I have tried fiddling with the timing at this level, which hasn't helped. The jetting should be fine and is as follows. Choke 30 Aux. Venturi 4.5 Main Jet 115 Emulsion Tube F16 Air Jet 160 Pump 50 Idler Jet 45F9 Some people are telling me too lean, others are saying too rich. The only components I have yet to change on the system since rebuild are the coil and the plugs... Has someone had this issue before and managed to fathom it out?! Cheers, Mike.